Estimation of the Local Seismic Amplification on an Industrialized Site in the French Rhône Valley

Gelis, Céline; Cauchie, Léna; Cushing, Edward Marc; Froment, B.; Franco, S.; Jomard, Hervé; Moiriat, Denis; Provost, Ludmila; Sariguzel, B.; Tebib, Haifa

doi:10.1007/s00024-022-03069-x

Cited by 6 publications

(5 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Tricastin region (French Rhone Valley, Fig. 1a) is located on top of an elongated valley that was dug during the Messinian Salinity Crisis in Cretaceous sandstones and limestones and that is now filled with Pliocene and Quaternary sediments (sands and clays, Gélis et al 2022). The site is interesting to study for several reasons.…”

Section: Context Of the Studymentioning

confidence: 99%

“…Three nodes were co-located with three seismic stations (called ADHE, BOLL and PAUL, Fig. 1) that have been deployed intermittently since 2016-2017 and have therefore recorded the seismicity for several months (Gélis et al 2022). BOLL and PAUL sites are located on top of the sedimentary filling whereas ADHE is placed on top of the cretaceous outcrop.…”

Section: Data Acquisitionmentioning

confidence: 99%

“…BOLL and PAUL sites are located on top of the sedimentary filling whereas ADHE is placed on top of the cretaceous outcrop. Gélis et al (2022) showed almost flat H/V ratio with a value around 1 between 0.2 and 10 Hz at ADHE and therefore used this station as rock-reference for SSR computation.…”

Section: Data Acquisitionmentioning

confidence: 99%

“…40 is commonly chosen as the value of parameter b: this has been found to be a good compromise to efficiently smooth the spectra without oversmoothing. We benefit from SSR computed by Gélis et al (2022) at sites BOLL and PAUL relative to ADHE (following eq. 4) for comparison.…”

Section: Spectral Ratios Computationmentioning

confidence: 99%

“…4) for comparison. We invite the reader to refer to Gélis et al (2022) for details regarding the SSR computation. Using co-located nodes at BOLL and PAUL (see Section 2.2), we computed the SSRh at each sensor sx, either considering BOLL or PAUL as a local site reference (eq.…”

Section: Spectral Ratios Computationmentioning

confidence: 99%

See 4 more Smart Citations

Insights into the conditions of application of noise-based spectral ratios in a highly industrialized area: a case study in the French Rhone Valley

Gisselbrecht

Froment

Boué

et al. 2023

Geophysical Journal International

View full text Add to dashboard Cite

Summary The local ground motion amplification related to the geology at a specific site (i.e. the so-called site effects) may be classically quantified through the SSR (Standard Spectral Ratio) technique applied on earthquake recordings. However, such a quantification might be challenging to carry out in low-to-moderate seismicity regions. Methods based on background ambient noise, such as noise-based Standard Spectral Ratio (SSRn), might be of great interest in these areas. But noise-derived amplification is particularly sensitive to local anthropogenic sources, which may introduce biases in the evaluation of site effects by dominating the geological effects, especially for frequencies higher than 1 Hz. A hybrid approach (SSRh), developed to reduce biases in noise-based spectral ratios by combining classical earthquake-based spectral ratio (SSR) and SSRn, was recently introduced and relies on a site-reference. We here investigate the applicability of SSRn and SSRh in a heavily industrialized environment in the Tricastin Valley (South-East France), where critical facilities are located. We continuously recorded ambient noise from February to March 2020 on a 400-sensor seismic array covering an area of about 10 km by 10 km. We demonstrate that SSRn and SSRh computed below 1 Hz are able to reproduce amplification factors provided by SSR. By contrast, at frequencies higher than 1 Hz, SSRn strongly deviates from SSR. SSRh shows closer results to SSR but presents a dependence to the choice of the local site-reference, thereby questioning the possibility to use SSRh blindly to estimate the local amplification in our context. These discrepancies reflect the impact of local anthropogenic sources. We therefore introduced a two-step workflow to mitigate the influence of local sources. The first step is to define a characteristic time window to optimally isolate significant transient signals. The second step consists in selecting the time segments that do not contain these transients with a clustering-based approach. By applying this workflow, we were able to remove some strong anthropogenic transient signals likely to be generated by local sources at some sites and therefore to locally improve the amplification assessment through noise-based spectral ratios. However, stationary sources, whose impact cannot be removed through our procedure, remain a major issue. This study provides some insights into the application of SSRn and SSRh in noisy industrialized areas, especially regarding the impact of local noise sources. It illustrates the difficulty of having a procedure for mitigating the impact of these sources that is efficient everywhere inside such a complex anthropized environment, where different types of sources (including stationary sources) cohabit.

show abstract

Section: Context Of the Studymentioning

confidence: 99%

Section: Data Acquisitionmentioning

confidence: 99%

Section: Data Acquisitionmentioning

confidence: 99%

Section: Spectral Ratios Computationmentioning

confidence: 99%

Section: Spectral Ratios Computationmentioning

confidence: 99%

See 3 more Smart Citations

Insights into the conditions of application of noise-based spectral ratios in a highly industrialized area: a case study in the French Rhone Valley

Gisselbrecht

Froment

Boué

et al. 2023

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

Regional physics-based simulation of ground motion within the Rhȏne Valley, France, during the MW 4.9 2019 Le Teil earthquake

Smerzini

Vanini

Paolucci

et al. 2022

Bull Earthquake Eng

View full text Add to dashboard Cite

In this paper, a comprehensive validation exercise of 3D physics-based numerical simulations (PBS) of seismic wave propagation is presented for a low-to-moderate seismicity area in the south east of France, within the Rhône River Valley, that hosts several operating nuclear installations. This area was hit on Nov 11, 2019, by an unusually damaging Mw 4.9 earthquake (Le Teil event). The numerical code SPEED ( http://speed.mox.polimi.it/ ), developed at Politecnico di Milano, Italy, was used to validate the simulations against the available recordings. When comparing simulations with records, a good to excellent agreement was found up to 8-10 Hz, showing that, even without a very detailed 3D numerical model of the medium, the PBS may provide realistic broadband predictions of earthquake ground motion. This also demonstrates that PBS, if suitably calibrated and validated, may be either an alternative or a useful complement to empirical ground motion models. Referring to the seismic risk evaluation of strategic and critical structures, infrastructures and industrial plants, such as nuclear power plants, the failure of which during an earthquake may endanger safety of population and cause environmental disasters, the 3D PBS may throw light on region-and site-specific features of ground shaking, especially in near-source conditions, that are typically poorly constrained in empirical models.

show abstract

Messinian canyons morphology of the Rhône and Ardèche rivers (south-east France): new insights from seismic profiles

Do Couto,

Cushing,

Mocochain

et al. 2024

BSGF - Earth Sci. Bull.

View full text Add to dashboard Cite

12 available two-way time high-resolution seismic reflexion profiles located on the central part of the middle Rhône valley have been interpreted. In addition, one of the profiles was reprocessed to determine the P-wave velocities of the main geological units and to convert this line into a depth cross-section. On all these profiles, the Lower and Upper Cretaceous units are clearly identifiable, as is the Messinian Erosion Surface (MES) carved out during the Messinian Salinity Crisis (MSC) by the paleo Rhône and its tributaries, the Ardèche and Cèze paleo-canyons. The Plio-Quaternary fill of these paleo-canyons shows at least 4 main units showing an overall transgression. The combination of geological data from geological maps, geological field surveys and borehole data has made it possible to model the MES in 3D at the scale of the region, and in depth/altitude. This surface is compared to the velocity contrast surface that could be derived from the H/V method, highlighting some differences in interpretation between the two geophysical methods. From a geological point of view, the interpretation of the seismic lines led to propose a reconstruction of the stages in the sub-aquatic filling of the Messinian-Pliocene aggradation of the paleo-river. Several occurrences of Mass Transport Deposits (MTDs) were identified during the fall of the Mediterranean sea level as well as during the rise of sea level. From a geomorphological point of view, this study provides new information on the route and longitudinal profile of paleo-rivers and, in particular, it deepens the profile of the Paleo-Rhône at the latitude of the Tricastin region (up to 700m bsl) and significantly modifies the course of the Ardèche as proposed in previous studies. The Paleo-Ardèche river, known to develop a karstic system during the MSC, is connected to a deep canyon, most likely through a karstic pocket valley as suggested by the very steep longitudinal profile of the MES. Finally, from a structural point of view, interpretation of the seismic lines shows a broad ENE-trending anticlinal structure associated with a normal fault apparently not affecting the Mio-Pliocene fill. In the southern part of the area, near the Uchaux anticline, the imaged structures suggest the presence of a recent (syn to post-Pliocene) fold propagation fault. In addition to all the new information provided by this study on the geology, morphology and methods of excavation and filling of the Messinian paleocanyon, the proposal of a topographic model of the paleo-canyon is crucial for modelling seismic movement in the context of a basin with a complex geometry and, in particular, for the numerical assessment of site effects in a context of low seismicity.

show abstract

Estimation of the Local Seismic Amplification on an Industrialized Site in the French Rhône Valley

Cited by 6 publications

References 60 publications

Insights into the conditions of application of noise-based spectral ratios in a highly industrialized area: a case study in the French Rhone Valley

Insights into the conditions of application of noise-based spectral ratios in a highly industrialized area: a case study in the French Rhone Valley

Regional physics-based simulation of ground motion within the Rhȏne Valley, France, during the MW 4.9 2019 Le Teil earthquake

Messinian canyons morphology of the Rhône and Ardèche rivers (south-east France): new insights from seismic profiles

Contact Info

Product

Resources

About